Vacuum spark advance



Jan. 28, 1941. I c SEYMOUR 2,229,822

VACUUM SPARK ADVANCE Filed July 27, 1938 3 Sheets-Sheet l Jan. 28, 1941. c. B. SEYMOUR VACUUM SPARK ADVANCE Filed July 27, 1938 3 Sheets-Sheet 2 a w a W 4 2 n 4 5 W 4 V m w n a W w n ILEIIII/O .l H H w I fl fi a m W W .2 WW .6 W 2 0% MM MM J a. V c 7 a a a 6 W n 4 v 2 4 0 0 w w 6 W fi F V fi H A m a i 4 4 a w a g a a a w M 5 Jan. 28, 1941. c. B. SEYMOUR 2,229,822

VACUUM SPARK ADVANCE Filed July 27, 1358 3 Sheets-Sheets 4 yMWY%- v i 5 Patented Jan. 28, 1941 PATENT OFFICE VACUUM SPARK ADVANCE Clayton B. Seymour, Chicago, Ill., assignor to Hoof Products Company, a corporation of Illinois Application July 27, 1938, Serial No. 221,598

7 Claims.

My invention relates to improvements in automatic spark advance mechanism for internal combustion motors.

My invention relates more particularly to improved mechanism of the type described adapted to be operated by the vacuum or sub-atmospheric pressure in the intake manifold of the motor to vary the spark in accordance with the load on the motor and thus assist the usual mechanical or centrifugally operated spark advance mechanism commonly used today. Internal combustion engines of the automotive type have for a number of years been universally equipped with an automatic device embodied in the ignition distributor to advance the spark automatically. This device was of the centrifugal type and the amount of advance depended entirely on speed, the spark advance increasing as the speed increased, and there was no provision made for varying the spark at a constant speed and a variable load. The method was quite satisfactory as long as the car was driven on a level road, but while climbing a hill, coasting or driving down a slight incline at the same speed, the constant spark advance provided by the device incorporated in the distributor did not permit the engine to run sufficiently smooth.- Thus if the spark was adjusted initially for good fuel economy at light load it would tend to introduce knocking at heavy load, and if the amount of spark advance was sufiiciently reduced to prevent knocking at heavy load, the fuel economy and smoothness at light load became unsatisfactory.

Recently a device has been developed and applied to several well-known automobiles which, in addition to the regular centrifugal spark advance incorporated in the distributor, provides means for varying the spark in accordance with the load on the engine. Such a device generally takes the form of a diaphragm or piston connected by a conduit to the intake manifold. The movement of this diaphragm is resisted by a spring and the motion thereof is transmitted to the arm of the ignition distributor, the arrangement beinggenerally such that the higher the vacuum the greater the amount of the spark advance. The conduit from the diaphragm has usually been connected to the carburetor at a point adjacent the carburetor valve Where with the carburetor valve closed the conduit is open to atmospheric condition in the carburetor above the valve but adapted upon movement of the valve to be transferred to the motor side thereof where it is subject to the reduced pressure in the intake manifold. Although this type of vacuum spark advance has been generally satisfactory, it was found lacking in performance under some conditions. Also, with the advent of suction controlled or vacuum operated governors and their widespread adoption by automobile owners and other users of internal combustion motors, the operation of the above mentioned type of vacuum spark advance mechanism was prevented. This was due to the fact that with a governor valve disposed in the intake manifold on the motor side of the carburetor valve, and with a governor valve controlling the flow of fuel to the motor, the pressure conditions formerly present adjacent the carburetor valve changed and under certain conditions were transferred to a point between the intake manifold and the governor valve. Consequently, mechanism was provided for automatically transferring the location of the diaphragm conduit connection with the intake manifold from a point near the carburetor valve to a point near the governor valve, whenever the governor valve assumed control of the flow of fuel to the motor. Several different types of such mechanism are on the market today.

Certain disadvantages, however, flow from the principal object of my invention is to provide an improved vacuum spark advance operating mechanism in the nature of a unit adapted to be inserted in the conduit to the intake manifold between the carburetor and the governor.

A further object of the invention is to provide a unit of the type described capable of connecting the vacuum spark advance to a point in the carburetorconduit adjacent the valve therein or automatically establishes communication between the diaphragm of the spark advance and the pressures in the carburetor or the intake manifold to advance or retard the spark in direct relation to the load and the speed of the engine,

particularly when a governor is inserted between the carburetor and the intake manifold.

A further object of the invention is to provide an improved unit of the class described capable of automatic operation to connect the diaphragm of the vacuum spark advance to the pressure in the intake manifold or at a point adjacent the carburetor valve.

A further object of the invention is to provide a unit capable of insertion between the carburetor and the governor, capable of operating the vacuum spark advance under certain conditions by the variance in pressure in the conduit between the carburetor valve and the governor valve.

Other objects and advantages will be more apparent from the following description wherein reference is had to the accompanying three sheets of drawings upon which Fig. 1 is generally a diagrammatic view illustrating the automatic spark advance the carburetor, governor and internal combustion engine with my improved unit disposed between the carburetor and the governor;

Fig. 2 is a vertical. sectional view through a conventional type of distributor;

Fig. 3 is a plan view of the same with the cover removed showing the centrifugal means for advancing the spark;

Fig. 4 is a plan sectional view through my improved vacuum spark advance unit taken generally on the lines 44 of Fig. 1;

Fig 5 is a diagrammatic sectional view taken through the carburetor unit governor and intake manifold showing generally the air conduits which form the connections between the same. Fig. 5 is a view showing an actual operating condition where the carburetor valve is open and the governor valve is in control of the flow of fuel mixture to the internal combustion engine;

Fig. 6 is a generally diagrammatic view similar to 5 showing an actual operating condition as for example, when. the internal combustion engine is running. at an idling speed and the governor is not controlling the flow of fuel mixture to the engine; and

Fig. 7 is a plan sectional viewsimilar to Fig, 2 with the parts in a changed position in accord.- ance with the condition shown in Fig. 6, and is taken generally on the line 'I-'I of'Fig. 6.

In the embodiment of my invention which I have illustrated, I have shown a conventionaldistributcr l0 having the usual arm I 2 pivotally connected to a rod [4 attached to one side of a diaphragm it. The diaphragm I6 may be mounted in a housing l8 having its chamber 20 open to atmosphere and a chamber 2 2 on the opposite side of the diaphragm connected to a conduit 24. A coiled spring 25 normally holds the diaphragm in the position shown in Fig. l, or in what is known as. a retarded position, a pin 2! and slot 29 in the arm 12 determining the extent of movement of the rod M, The above construction is well known in the art and for that reason will not. be described in further detail herein.

The distributor H1 is provided with the usual type of centrifugal spark advance 28 which in;- cludes the weights 3%! normally held in the position shown in Fig. 3 by the springs 32 but which, when the distributor driveshaft 34 revolves at a continual increasing rate of speed fly outwardly and in the usual manner advance the timing of the ignition.

In the usual construction of automotive engines, the conduit 24' is directly connected to a port 10- -from the governor housing 10.

and the reduced portions 92 and 94.

cated slightly above the throttle valve in the conduit of a down-draft carburetor. In this manner, as the speed of the engine increases, the suction produced below the carburetor valve will effect the diaphragm 16 to advance or retard the spark in direct ratio to the load and speed at which the vehicle is operating, This is usual in well-known constructions and has been commercially used for a considerable length of time. However, as previously explained, when a governor is employed with the usual internal combustion engine the pressure conditions formerly present adjacent the carburetor valve change and are transferred to a point beyond the governor valve, thus rendering ineffective the operation of the diaphragm I6 by reason of the fact that the pressure conditions in the conduit at the carburetor valve will be more or less atmospheric.

In the construction which I have provided, I extend the conduit 24 to a bushing 36 suitably mounted in a screw-threaded opening 38 in a unit 40 that is securely fastened in position between the carburetor C and a vacuum operated governor G by the usual fastening bolts 42. The carburetor C, unit 40, and governor G may have the aligned substantially square conduits 44, 46 and 48 respectively communicating with the opening 50 to the intake manifold 52 of the internal combustion engine E.

The carburetor C may be provided withthe usual balanced butterfly valve 54 mounted for rotation upon a suitable shaft 56 which when it is moved to a closed or idling position is located slightly below a vent 58 in the side of conduit 44.

The vent 58 communicates through the bushing mechanism which is in the housing may be of the usual type shown in the patent to Addison C. Hoof, No. 1,966,722.

The conduit I2 may be connected} to the intake manifold 52 by a suitable bushing. The opposite end of the conduit may be connected to the unit 40 by a similar bushing 16 screw-threadedly mounted in the opening 18.

The unit 4!! is provided with means for efiecting communication between the various conduits 2'4, 62 and 12, This means may include a passageway aligned with the screw-threaded opening65. A pair of drilled openings 82 and 84 providecommunication between the conduits 24 and 12 with the passageway 80.

A slidable valve member 86 is adapted to be mounted in the passageway 80-. This valve may be formed with the enlarged portions 88- and 90 A coiled spring member 95, positioned against the enlarged shoulder 99, normally holds the valve in the position shown in Fig. 4 against the openheaded cap 9| at the end of passageway 80. A

drilled opening 91 connects the end of passageway 80' with the conduit 43 through the unit 40.

The operation of the unit in conjunction with the diaphragm I5 of the automatic spark advance will now be described, In the position shown in Figs. 4 and 5, the vehicle, which is driven by an internal combustion engine, may be travelling along at a governed speedof for example forty miles an hour; To obtain this condition of operation, the carburetor valve 54will be in the wide open position shown in Fig. 5 and'the governor valve 56' will be in the partially closed position The governor shown in the same figure. It will be obvious that the condition in the conduit 44 of the carburetor, 46 of the unit, and 48 of the governor above valve 66 will be generally atmospheric. As a result there will be no suction through conduit 62 or through the passageway 91, and the spring member 96 will move the valve 86 to the position shown in Fig. 4. In this position of the valve 86,.conduit from the distributor will be connected directly through the unit 4!! to the conduit 12 attached to the intake conduit of the engine. In this position the diaphragm 16 will then be in direct control of the pressure condition in the intake conduit 52 and because this is sub-atmospheric due to the position of governor valve 66, the spark will be advanced in direct relation to the sub-atmospheric condition in the intake man ifold.

In Figs. 6 and 7 I have illustrated the conditions which are present when the automotive engine is idling; such a condition as for example where the vehicle is parked at a curbor the engine is running in any other manner without load. The manually operated carburetor valve 5 1 will thus be in a closed position with the valve slightly below the vent 58 so that the conduit 52 will be subject to atmospheric pressure. The governor valve 66 will be in generally Wide open position, shown in Fig. 6.

With the carburetor valve closed, as described, there will be a certain amount of suction or a sub-atmospheric condition below the carburetor valve 54 in the conduit 44 of the carburetor, 46 of the unit 40 and 48 of the governor. By reason of the sub-atmospheric condition below the carburetor valve 54, suction through the passageway 91 will overcome the resistance of spring 96 and move the valve 86 to the position shown in Fig. 7. This movement will effect a communication between the diaphragm l6 of the distributor through the conduit 24 and the conduit 62 with the atmospheric condition prevailing above the carburetor valve and as a result there will be no advance of the spark. It will be noted, however, that as soon as there is sufficient movement of the carburetor valve to an open position to place the vent 58 below the edge of the carburetor valve, that the suction at this point in combination with the compression of spring 96 will be sufliciently great to immediately move valve 86 back to the position shown in Fig. 4, thus connecting the conduit 24 directly to the intake manifold, thereby securing a spark advance con sistent with the condition in the intake manifold.

From the above and foregoing description it will be apparent to those skilled in the art that I have provided a comparatively simple unit capable of insertion between the carburetor and the governor of any of the standard carburetors and governors in commercial use to-day which will effectively keep the control of the automatic spark advance under the condition present in the intake manifold in any and all stages of operation except when the carburetor valve is closed and the engine is idle.

WhileI have illustrated and described a specific embodiment of my invention, it will be apparent to those skilled in the art that changes and modifications may be made in the exact details shown and I do not wish to limit myself in any particular. Rather what I desire to secure and protect by Letters Patent of the United States is:

1. In an internal combustion engine, in combination a fuel intake conduit, a manually actuated throttle valve therein, an automatically actuated throttle valve in said conduit, ignition mechanism, vacuum operated means to adjust said mechanism to vary the timing of the spark and means for placing said vacuum means in communication with said fuel intake conduit at said manually actuated throttle valve when the throttle valve is substantially closed and for placing said vacuum means in communication with said conduit on the engine side of said governor valve when said manual valve is open, said means including a unit having a conduit forming part of said intake conduit and. located between said manual and automatically actuated valve.

2. In an internal combustion engine, in combination a fuel intake conduit, a manually actuated throttle valve therein, an automatically actuated throttle valve in said conduit, ignition mechanism, vacuum operated means to adjust said mechanism to vary the timing of the spark, means for placing said vacuum means in communication with said fuel intake conduit at said manually actuated throttle valve or for placing said vacuum means in communication with said conduit on the engine side of said governor valve when said manual valve is open, said means comprising a unit located between said manual and automatically actuated valves, and a valve therein operated by the pressure differential on the two sides of said throttle valve, said valve connected to the fuel intake conduit at said manual throttle, also on the engine side of said automatically operated throttle valve and also between said valves.

3. In an internal combustion engine, in combination a fuel intake conduit, a carburetor valve mounted therein, an automatically actuated governor valve in said conduit, ignition mechanism, vacuum operated means to adjust said mechanism to vary the timing of the spark, and a separable unit interposed in the conduit and including a transfer valve arranged to place said vacuum means in communication with said conduit at a point on the engine side of said governor valve when said manual valve is open and in communication with said conduit at said carburetor valve when said manual valve is at or near closed position, said unit positioned between the manual valve and the automatically actuated valve and in communication with said intake conduit between said carburetor and governor valves and also on the engine side of said governor valve.

4. In an internal combustion engine, in combination a fuel intake conduit, a carburetor valve mounted therein, an automatically actuated governor valve in said conduit, ignition mechanism, vacuum' operated means to adjust said mechanism to vary the timing of the spark, and

. a transfer valve arranged to place said vacuum means in communication with said conduit at a point on the engine side of said governor valve when said manual valve is open and in communication with said conduit at said carburetor valve when said manual valve is at or near closed position, said transfer valve position between the manual valve and the automatically actuated valve and operable to connect the vacuum operated means to the intake conduit at the carburetor valve or beyond the governor valve depending on the differential in pressure on the two sides of the carburetor valve.

5. In an internal combustion engine, in combination an intake conduit, an intake manifold at the end of said conduit, a manual throttle valve in said conduit, an automatic governor of the manual throttle valve, an ignition device for said engine, vacuum operated means for adjusting said ignition device to advance the time of sparking, a vacuum take-off in said conduit adjacent the manual throttle valve, a vacuum take-off in the intake manifold beyond said governor valve, and means to connect either takeoff to said vacuum operated means, said means including a unit forming part of said intake conduit and interposed between the two valves and having a valve member operable by differential pressure on the two sides of the manual throttle valve.

6. In an internal combustion engine equipped with ignition mechanism and vacuum operated means for adjusting the same to vary the spark advance, the combination with a manual throttle in the intake conduit, an automatic governor having a throttle in the intake conduit on the engine side of the manual throttle, a vacuum take-ofi aperture adjacent the manual throttle, a vacuum take-01f connected to the conduit on the engine side of the governor throttle, and a valve to connect either aperture to said vacuum operated means, said valve operable by pressure differential on the two sides of the manual throttle.

'7. For use in combination with an internal throttle valve in the conduit on the engine side combustion engine comprising an ignition mechanism, vacuum operated means to adjust said mechanism to vary the timing of the spark, and a fuel intake conduit having a manifold and a carburetor throttle valve therein; the improvement which comprises a unit adapted to be separably arranged in said intake conduit between said manifold and said throttle valve and providing a valveless port adapted to form a portion of said fuel intake conduit in operative position, said unit being provided with an automatic transfer valve, said valve having a portion communieating with said port and being provided with means for association with the conduit adjacent said throttle valve whereby to control the position of the transfer valve in accordance with the differential in pressure on the two sides of the throttle valve, said unit comprising conduit means for connecting said valve with said vacuum operated means, and conduit means for connecting said valve with the intake manifold vacuum, said valve being adapted in one operative position to place the vacuum operated means in communication with the intake manifold and in another position to place said vacuum operated means in communication with said intake conduit adjacent the throttle valve.

CLAYTON B. SEYMOUR. 

